Laboratory Operations and QC Flashcards
7 cards from real Medical Laboratory Technician Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Laboratory Operations and QC flashcards as text
Which of the following is the BEST indicator that a pipette is in need of recalibration?
Answer: QC results show a sudden positive shift across multiple analytes
A sudden positive shift in multiple analytes often points to a volumetric error such as a pipette delivering too much sample.
Carryover in automated analyzers refers to:
Answer: Contamination of a sample by residual material from a previous sample
Carryover occurs when residual material from a prior sample contaminates the next sample, falsely affecting its result.
A laboratory is comparing results from a new method to an established reference method. The best statistical tool to evaluate proportional bias is:
Answer: Passing-Bablok regression
Passing-Bablok regression evaluates agreement between two methods and can detect both constant and proportional bias.
A spectrophotometer reads a standard solution that should have 0.400 absorbance but displays 0.398. This difference is an example of:
Answer: Random error only
A single small deviation from the expected value is consistent with random (imprecision) error rather than a consistent systematic bias.
In laboratory quality management, 'total allowable error' (TEa) defines:
Answer: The maximum error acceptable for a test to be clinically useful
TEa is the maximum permissible combination of imprecision and inaccuracy for a test result to remain clinically meaningful.
Which of the following BEST describes the purpose of an internal quality control (IQC) program?
Answer: To monitor day-to-day precision and accuracy of testing processes
IQC monitors the ongoing performance of the testing process within the laboratory to detect errors before patient results are reported.
A laboratory records the following QC results for sodium: 139, 138, 141, 137, 140, 142, 138 mEq/L (mean=139, SD=1.7). The R-4s rule compares:
Answer: The highest and lowest results within a single run to the 4 SD range
The R-4s rule is violated when the range between the highest and lowest QC result within one run exceeds 4 SD, indicating random error.